Germ cell tumors in the basal ganglia: problems of early diagnosis and treatment

Intracranial germ cell tumors (GCTs) originating in the basal ganglia are rare. The authors investigated factors related to the diagnosis of these lesions as well as outcome in order to help decrease the time to diagnosis and improve treatment efficacy.

The authors reviewed the clinical features of 142 cases of intracranial GCT in their institute. Fourteen cases of basal ganglia GCT were identified. The symptoms, neuroimaging findings, delay between symptom onset and diagnosis or treatment, initial and further treatment, and outcome were investigated.

Major symptoms were motor weakness and precocious puberty. Gadolinium-enhanced T1-weighted MR images showed enhancement in 8 of 11 patients examined, but only slight hyperintensity without enhancement in 2 patients. Ipsilateral peduncle and hemispheric atrophy were found in 3 and 4 patients, respectively. Cases of basal ganglia GCT were characterized by a longer delay from the initial neuroimaging examination to diagnosis compared with GCT in other regions. Five patients had aggravated hemiparesis in the extremities due to the delay in diagnosis. Despite good response to the initial therapy, 5 patients experienced recurrence; 2 of these 5 had malignant GCTs, and 3 had been treated only with chemotherapy or radiochemotherapy with insufficient radiation dose and field. Finally, the 2 patients with malignant GCTs died of the disease, and 1 died of aspiration pneumonia due to dissemination around the brainstem.

Early diagnosis requires MR imaging with administration of contrast medium in young patients presenting with motor weakness and/or precocious puberty. Serial neuroimaging studies should be performed if any tiny lesion is detected in the basal ganglia. Since insufficient treatment resulted in early recurrence, radiation therapy with adequate dose and field is essential.